Acoustical ceiling



p 1963 w. B. BALL, JR 3,104,731

ACOUSTICAL CEILING Filed Sept. 20, 1960 2 Sheets-Sheet l 38 LMVVNQWW/[AQ 1 A 1 I. I

' INVENTOR.

'W/LLMM 5 BALL JR.

/ ATTORNEYS p 1963 w. B. BALL, JR 3,104,731

ACOUSTICAL CEILING Filed Sept. 20, 1960 2 Sheets-Sheet 2 INVENTOR. H/lum/v B. 5444 J0.

ATTORNEYS United States Patent Ofiice 3,164,731. ACOUSTECAL CEEHNG William B. Ball, 52:, Darien, (Conn, assignor to Owens- Corning Fiherglas Corporation, a corporation of Delaware Filed Sept. 20, 196%, fier- No. 57,391 3 Claims. (Cl. 1811-33) This invention relates to acoustical tile for damping and confining sound energy, and more particularly to acoustical tile ctor installation in abutting series to form, for example, an acoustical ceiling spaced below a main ceiling structure.

The use of acoustical t-ile, mechanically suspended from a main ceiling structure to form false ceilings, has become widespread in recent years. Such structures, in addition to soundproofing the room, also provide an inexpensive method of altering the high ceiling constructions of older buildings to conform to the modern design concept of lower ceilings.

One of the most effective sound deadening materials used ior acoustical tile is a porous fibrous mat of mineral fibers. Mineral fibers are lightweight, thus permitting the use of inexpensive support structure for suspending the tiles from ceilings. At the same time, mineral fibers have very good properties of sound absorption and, thus, are well suited for use in acoustical tiles.

A mat of mineral fibers does not, however, have the necessary strength characteristics to be used alone as a tile. One method, and the method employed in the present invention, tor utilizing a mineral fiber mat for a tile is to provide a support structure, such as a pan or tray, for containing the fibrous mat.

There are several characteristics desired in such a pan which prior art pans have not completely satisfied. It should be lightweight, it should be capable of being made in large sizes so that one tile structure will span a large area, and it should be so constructed that the exposed surface facing into the room and forming the visible ceiling can be washed or painted without damage to the acoustical properties of the tile. The pan of this invention fulfills each of these requirements.

It is an object of this invention to provide an acoustical tile structure incorporating mats of fibrous material supported and contained within a pan.

Another object of the invention is to provide an acoustical tile that is fire resistant, of low cost and easy installation, and durable in use.

Another object of the invention is to provide a pan for an acoustical tile, the pan having reinforcing ribs on the bottom wall and integral therewith which permit the pan to be of relatively thin wall thickness while still being made in large sizes to span large areas without buckling.

Another object of the invention is to provide a pan structure having reinforcing ribs on the upper or back surface of the pan bottom whereby to space a fibrous mat of mineral fibers away from the pan bottom wall to provide an air chamber between the pan bottom wall and the fibrous mat which acts as a sound deadener.

A turther object of the invention is to provide an acoustical tile structure including a pan and a fibrous mat disposed therein, the pan having a perforated bottom wall for the passage of sound energy therethrough, the pan bottom having means spacing the fibrous mat from the bottom wall, whereby a dead air space is provided intermediate the pan and the mat so that the exposed bottom 3,104,731 Patented Sept. 24, 1963 surface of the pan can be washed or aging the fibrous mat.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In the drawings:

FIGURE 1 is a perspective view of an acoustical tile assembly of this invention showing the manner of insertion of the fibrous mat into the pan;

FIGURE 2 is a perspective view of the acoustical tile of FIGURE -1 showing the fibrous mat assembled in the p FIGURE 3 is a sectional view of the tile of FIGURE 2 taken substantially along the plane 33;

FIGURE 4 is a fragmentary plan view of the perforated bottom surface of the pan of FIGURE 1;

FIGURE 5 is a perspective view, with parts broken away and in section, of the acoustical tile of FIGURE 2 installed in abut-ting series on a grid system suspended from a main ceiling structure;

FIGURE 6 is a bottom perspective view of the acoustical tile of FIGURE 1;

FIGURE 7 is a sectional view similar to FIGURE 3 showing a modified form of the rib structure; and

FIGURE 8 is a partial side elevational view in section of two tiles in abutting relationship each tile" being sectioned substantially along line 88 of FIGURE 7 looking in the direction of the arrows.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Briefly, the acoustical tile 10 comprises two basic elements: a pan 1?. and a fibrous mat of mineral fibers 14. The pan is open-topped and has a perforated, sound admitting bottom wall 20 with four upstanding side walls 2225. An upstanding reinforcing rib structure (comprising ribs 26, 27) is provided on the bottom wall of the pan. The porous fibrous mat of mineral fibers 14 has a sound admitting surface 17 on one side and an oppositely disposed surface 19 provided with an air impervious medium 18 secured htereto. The fibrous mat is snugly contained (FIGURES 2 and 3) within the pan side walls with the sound admitting surface 17 in abutment with the upper extremity of the bottom wall rib structure. A sound-deadening air chamber 30 is formed in the space between the pan bottom wall and the fibrous mass.

The fibrous material '16 of the mat 14 may be any fibrous material having sound quieting properties. For example, rock wool or cane fibers may be used.

However, it is preferred that the fibrous material be glass fibers. Glass fibers are desirable because they are light in weight, are perfectly clean, do not attract moisture, and have very high fire resistance. The mat is preferably composed of fine glass fibers less than twenty hundred thousandths of an inch in diameter in a slightly compressed and bonded mass having shape-retaining properties and a density of about three-fifths of a pound per cubic foot. A phenol formaldehyde resin is recompainted without damwhich is of generally rectangular shape.

' 'tile.

' the bottom wall.

mendedias a binder component for the fibrous mass but If desired, the

attached in a continuous fashion to the surface of the I fibrous mass. The medium 18 may be, for example, painted on as a paint or it may be a film such as metal foil adhered to the fibrous glass. j

The air impervious layer 13 greatly increases the transmission loss through the fibrous body. Very few of the sound waves are passed through the acoustical tile and thus the tile more nearly fulfills the objective of soundproofing. The provision of such a coating is more fully explained in. copending' application Serial No. 11,222 filed February 26, 1960. r The fibrous mat is shaped to fit snugly into the pan 12,

The perforat-ions 2.1 of the bottom wall may be best seen in FIGURE 4. As will be noted, the perforations are of relatively small diameter but are spaced closely together to give maximum open area for the passing of sound energy. As will be noted, two of the pan side walls 22, 23 are perforated, while the other two walls 24, 25 are not. This configuration is dictated by the method of manufacture of the pan and is not necessary to the function of the In forming theipan, it is convenient to perforate an entire sheet of metal, starnp out the desired shape of the pan, and then form the ribs and bend the end portions up to form the side walls 22, 23. As shown, the end walls 24, 25 are provided as separate pieces and may be secured to the pan structure by means of welding or the like. However, if desired, the side walls 24, 25 may be formed integrally with the pan construction.

Asw-ill be noted, the parallel ribs 26, 27 forming the reinforcing'rib structure extend from end to end of the pan. bottom Wall. It is preferred that the ribs extend along the longest dimension of the pan to result in the best reinforcing. While the ribs are shown as circular in cross-section, other shapes may be employed and any suitable curved rib configuration may be employed. The ribs should, however, be upstanding as shown in order to space the fibrous mat from the bottom wall.

Tab members 28 are provided along the upper edges of the side Walls 22, 23. As will be noted in FIGURE 2, after the fibrous mat114 has been inserted into the pan, the tabs '28 are bent to a positioh extending over the fibrous mat to thereby retain the mat in place.

As shown in FIGURE 3, when the fibrous mat 14 has been inserted into the pan, the bottom surface 17 will abut against the ribs 26, 27, thus spacing the mat above The result-ant air chamber 30 serves to further deaden the sound which passes through the perbeneaththe T-beams and abut against a similar portion of an adjacent pan.

The construction of the ribs 26, 27 forms an important aspect of the invention. Forming the ribs with a curved tubularconfiguration and as an integral part of the pan bottom wall 20 accomplishes several useful functions. Aside from reinforcing the bottom wall, formation of the ribs integrally with the bottom wall provides parallel seams 42 on the bottom wall as shown in FIGURE 6. These seams are visible from the underside of the bottom wall when the entire structure is installed, and the seams form a desirable appearance feature in that they give the eifect of several tiles rather than one large tile.

As shown in FIGURE 7, the appearance feature of the seams may be further enhanced by providing a pair of outwardly and downwardly diverging wall portions 44, 46 extending from each tubular support element to the bottom wall 20. Additionally, the marginal, longitudinal edges of each bottom wall 20 is bevelled, as at 47. a The surfaces 4-4, 46 and the marginal edge portions 47 cooperably define a plurality of spaced, inverted V-shaped grooves as viewed from the underside of the bottom wall.

The appearance is similar to that of thebevelled joints f-orated bottom wall of the pan. The ribs 26 also serve two other functions. One is, of course, to reinforce the pan structure permitting the pan to be made of relatively thin wall section material but in large sizes whereby the pan will not readily buckle the remaining function of the ribs is to separate the fibrous body 14 from the bottom Wall of the pan. This is desirable because it permits washing or painting of the exterior surface of the pan bottom wall without damaging the fibrous body.

FIGURE 5 illustrates a plurality of the tiles 10 installed in abutting series to form a false ceiling. As will be noted, a grid structure is provided to support the tile. The grid structure may suitably comprise a series of spaced inverted T-beams 32 which are hung by wires 34 from joists 36 of the main ceiling structure 38-. little sired, the side walls 22, 23 of the pan 12 may be contoured to hide the T-beams 32. This may be done, for example, by providing indentations in the side walls of the pan whereby a portion of the pan would overlap intermediate smaller and more expensive acoustical tiles and consequently suggests to the viewer that the large tile comprises several small tiles.

A further modification of the inventionis shown in FIGURE 8. In this modification, the ribs 26 and 27 serve as conduits and may be used to carry electrical wires,plurnbing or the like. As will be noted, openings 43, 50 are provided in the end walls 24, 25 in registry with the ribs. These openings permit the extension of wires through the ribs from one tile 10 to the next tile 10. this way, the tiles may be used to run electrical wiring or other. elongated elements across the ceiling.

A further advantage of the curved construction of the ribs is that it presents a large surface area for. the seating and support of the fibrous mat 14. A large support surface is desirable in order to prevent sagging of the mat towards the pan bottom wall.

I claim:

1. An acoustical tile for installation in abutting series to dampen and confine sound energy comprising a pan bottom wall.

7 2. The combination to'form an acoustical tile comprising an open-topped pan having a perforated sound admitting bottom wall and upstanding side walls; an upstanding curved tubular reinforcing rib structure formed integrally with the bottom wall of the pan; a porous fibrous mass of mineral fibers having'a sound admitting surface on one side and an oppositely disposed air impervious surface; said fibrous mass being contained within the pan side walls with said sound admitting surface in abutment with the bottom Wall rib structure; and a sound-deadening air chamber formed in the space between the pan bottom wall and the fibrous mass.

3. An acoustical tile for installation in abutting series to dampen and confine sound energy comprising an opentopped pan having a perforated sound admitting bottom wall and upstanding side walls; a plurality of upstanding tubular ribs formed integrally with the bottom wall of the pan; each of said ribs extending from one side wall to an oppositely disposed'side wall; an opening in each of the last mentioned side walls in registry with each rib whereby each of 'saidribs serves as an open-ended conduit; a porous fibrous mass of mineral fibers having a sound admitting surface on one side and an oppositely disposed air impervious surface; said fibrous mass being contained within the pan side walls with said sound admitting surface in abutment with the bottom Wall ribs.

1,929,751 Macdonell Oct. 10, 193 3 Barnett Oct. 6, 1931 7 6 Randall Dec. 5, 1933 McNeil et al Apr. 16, 1935 Kellogg May 21, 1935 MacDonald Mar. 29, 1938 Lucius Nov. 12, 1940 Rapp Oct. 25, 1955 FOREIGN PATENTS France Dec. 8, 1954 

1. AN ACOUSTICAL TILE FOR INSTALLATION IN ABUTTING SERIES TO DAMPEN AND CONFINE SOUND ENERGY COMPRISING A PAN HAVING A PERFORATED BOTTOM WALL AND UPSTANDING SIDE WALLS; AN UPSTANDING REINFORCING RIB STRUCTURE FORMED INTEGRALLY WITH THE BOTTOM WALL OF THE PAN; AND A POROUS FIBROUS MASS OF MINERAL FIBERS HAVING A SOUND ADMITTING SURFACE AND AN OPPOSITELY DISPOSED SURFACE PROVIDED WITH AN AIR IMPERVIOUS MEDIA SECURED THERETO; SAID FIBROUS MASS BEING CONTAINED WITHIN THE PAN SIDE WALLS WITH SAID SOUND ADMITTING SURFACE IN ABUTMENT WITH THE BOTTOM WALL RIB STRUCTURE TO THEREBY SPACE THE FIBROUS MASS FROM THE BOTTOM WALL. 